Smooth roller



FIG. 1 is a top perspective view of the smooth roller, showing the new design;

FIG. 2 is a front view of the smooth roller;

FIG. 3 is a rear view of the smooth roller;

FIG. 4 is a side view of the smooth roller;

FIG. 5 is another side view of the smooth roller;

FIG. 6 is a top view of the smooth roller; and,

FIG. 7 is a bottom view of the smooth roller. 

The ornamental design for a smooth roller, as shown and described. 